| 1. |
- Dominguez, Mev, et al.
(författare)
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Functional implications of the p.Cys680Arg mutation in the MLH1 mismatch repair protein.
- 2014
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Ingår i: Molecular Genetics & Genomic Medicine. - : Wiley. - 2324-9269. ; 2:4, s. 352-355
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Tidskriftsartikel (refereegranskat)abstract
- In clinical genetic diagnostics, it is difficult to predict whether genetic mutations that do not greatly alter the primary sequence of the encoded protein causing unknown functional effects on cognate proteins lead to development of disease. Here, we report the clinical identification of c.2038 T>C missense mutation in exon 18 of the human MLH1 gene and biochemically characterization of the p.Cys680Arg mutant MLH1 protein to implicate it in the pathogenicity of the Lynch syndrome (LS). We show that the mutation is deficient in DNA mismatch repair and, therefore, contributing to LS in the carriers.
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| 2. |
- Joost, Patrick, et al.
(författare)
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Efficient and reproducible identification of mismatch repair deficient colon cancer : Validation of the MMR index and comparison with other predictive models
- 2013
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Ingår i: BMC Clinical Pathology. - : Springer Science and Business Media LLC. - 1472-6890. ; 13:1, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- Background: The identification of mismatch-repair (MMR) defective colon cancer is clinically relevant for diagnostic, prognostic and potentially also for treatment predictive purposes. Preselection of tumors for MMR analysis can be obtained with predictive models, which need to demonstrate ease of application and favorable reproducibility. Methods. We validated the MMR index for the identification of prognostically favorable MMR deficient colon cancers and compared performance to 5 other prediction models. In total, 474 colon cancers diagnosed ≥ age 50 were evaluated with correlation between clinicopathologic variables and immunohistochemical MMR protein expression. Results: Female sex, age ≥60 years, proximal tumor location, expanding growth pattern, lack of dirty necrosis, mucinous differentiation and presence of tumor-infiltrating lymphocytes significantly correlated with MMR deficiency. Presence of at least 4 of the MMR index factors identified MMR deficient tumors with 93% sensitivity and 76% specificity and showed favorable reproducibility with a kappa value of 0.88. The MMR index also performed favorably when compared to 5 other predictive models. Conclusions: The MMR index is easy to apply and efficiently identifies MMR defective colon cancers with high sensitivity and specificity. The model shows stable performance with low inter-observer variability and favorable performance when compared to other MMR predictive models.
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| 3. |
- Joost, Patrick, et al.
(författare)
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Heterogenous mismatch-repair status in colorectal cancer
- 2014
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Ingår i: Diagnostic Pathology. - : Springer Science and Business Media LLC. - 1746-1596. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Background: Immunohistochemical staining for mismatch repair proteins is efficient and widely used to identify mismatch repair defective tumors. The tumors typically show uniform and widespread loss of MMR protein staining. We identified and characterized colorectal cancers with alternative, heterogenous mismatch repair protein staining in order to delineate expression patterns and underlying mechanisms. Methods: Heterogenous staining patterns that affected at least one of the mismatch repair proteins MLH1, PMS2, MSH2 and MSH6 were identified in 14 colorectal cancers. Based on alternative expression patterns macro-dissected and micro-dissected tumor areas were separately analyzed for microsatellite instability and MLH1 promoter methylation. Results: Heterogenous retained/lost mismatch repair protein expression could be classified as intraglandular (within or in-between glandular formations), clonal (in whole glands or groups of glands) and compartmental (in larger tumor areas/compartments or in between different tumor blocks). These patterns coexisted in 9/14 tumors and in the majority of the tumors correlated with differences in microsatellite instability/MLH1 methylation status. Conclusions: Heterogenous mismatch repair status can be demonstrated in colorectal cancer. Though rare, attention to this phenomenon is recommended since it corresponds to differences in mismatch repair status that are relevant for correct classification. Virtual Slides: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1771940323126788
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| 4. |
- Jorgren, Fredrik, et al.
(författare)
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Ezrin expression in rectal cancer predicts time to development of local recurrence
- 2012
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Ingår i: International Journal of Colorectal Disease. - : Springer Science and Business Media LLC. - 1432-1262 .- 0179-1958. ; 27:7, s. 893-899
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Tidskriftsartikel (refereegranskat)abstract
- Improved outcome after rectal cancer surgery requires identification of novel risk factors of tumour recurrence in order to personalise therapy, that is, enhanced selection of high-risk patients to additional radiochemotherapy or intensified follow-up. In several tumour types, including colorectal cancer, high expression of the membrane-cytoskeleton linker ezrin has been suggested to impair prognosis but has not yet reached clinical application. We evaluated the expression of ezrin in rectal cancer with a focus on the identification of a marker for local tumour recurrence. Immunohistochemical expression of ezrin was analysed in 104 primary rectal cancers from patients who developed local recurrences despite being treated with R0 major abdominal surgery. Time to local recurrence and distant metastasis as well as 5-year overall and cancer-specific survival were used as end points. Ezrin expression was weak in 17% of the tumours, moderate in 62%, and intense in 21%. The time to local recurrence was significantly shorter (p = 0.0004) for patients with tumours showing high ezrin expression. No correlation between ezrin expression and time to distant metastasis was identified. Survival data were similar between groups irrespective of ezrin expression in the primary tumours. Our findings suggest that increased expression of ezrin may represent a marker of aggressive biological behaviour in rectal cancer. Although further validation is needed, ezrin may represent a relevant marker for personalised treatment of rectal cancer with respect to risk of local recurrence after R0 surgery.
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| 5. |
- Klarskov, Louise, et al.
(författare)
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Challenges in the Identification of MSH6-Associated Colorectal Cancer: Rectal Location, Less Typical Histology, and a Subset With Retained Mismatch Repair Function.
- 2011
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Ingår i: American Journal of Surgical Pathology. - 1532-0979. ; 35:9, s. 1391-1399
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Tidskriftsartikel (refereegranskat)abstract
- Identification of Lynch syndrome tumors is challenging. This relates particularly to MSH6-associated cases, which show reduced penetrance of colorectal cancer and a higher age at diagnosis. We recorded the clinical and morphologic features of 52 MSH6-associated colorectal cancers in comparison with MLH1/MSH2-mutant tumors and sporadic mismatch repair-deficient cancers. In the MSH6 subset, we confirmed a higher age (median, 56 y) at diagnosis and found a significantly larger proportion (25%) of rectal cancers. Presence of dirty necrosis was the sole histologic component that significantly differed between MSH6 and MLH1/MSH2 tumors. Compared with the sporadic mismatch repair-defective cohort, MSH6 cases had a lower prevalence of tumor-infiltrating lymphocytes and Crohn-like reactions. Mismatch repair defects were identified in 92% of MSH6 tumors, with high concordance between microsatellite instability and loss of immunohistochemical MSH6 expression. The remaining 8% showed a mismatch repair-stable phenotype, which suggests that analysis of additional tumors might be considered in families suspected of Lynch syndrome.
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| 6. |
- Seinen, Jojanneke M, et al.
(författare)
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Prognostic value of proliferation in pleomorphic soft tissue sarcomas: a new look at an old measure.
- 2012
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Ingår i: Human Pathology. - : Elsevier BV. - 1532-8392 .- 0046-8177.
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Tidskriftsartikel (refereegranskat)abstract
- Though proliferation has repeatedly shown a prognostic role in sarcomas, it has not reached clinical application. We performed a comprehensive evaluation of the prognostic role of 5 proliferation measures in a large series of soft tissue sarcomas of the extremities and the trunk wall. One hundred ninety-six primary soft tissue sarcomas of the extremities and the trunk wall were subjected to DNA flow cytometry for quantification of S-phase fraction and to immunohistochemical evaluation of Ki-67, Top2a, p21, and p27Kip1. In univariate analysis, positive expression of Ki-67 (hazard ratio = 4.5, CI = 1.6-12.1), Top2a (hazard ratio = 2.2, CI = 1.2-3.5) and high S-phase fraction (hazard ratio = 1.8, CI = 1.2-3.7) significantly correlated with risk for metastasis. When combined with currently used prognostic factors, Ki-67, S-phase fraction and Top2a fraction contributed to refined identification of prognostic risk groups. Proliferation, as assessed by expression of Ki-67 and Top2a and evaluation of S-phase fraction and applied to statistical decision-tree models, provides prognostic information in soft tissue sarcomas of the extremity and trunk wall. Though proliferation contributes independently to currently applied prognosticators, its role is particularly strong when few other factors are available, which suggests a role in preoperative decision-making related to identification of high-risk individuals who would benefit from neoadjuvant therapy.
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| 7. |
- Therkildsen, Christina, et al.
(författare)
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Cancer risks and immunohistochemical profiles linked to the Danish MLH1 Lynch syndrome founder mutation
- 2012
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Ingår i: Familial Cancer. - : Springer Science and Business Media LLC. - 1389-9600 .- 1573-7292. ; 11:4, s. 579-585
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Tidskriftsartikel (refereegranskat)abstract
- Founder mutations with a large impact in distinct populations have been described in Lynch syndrome. In Denmark, the MLH1 c.1667+2_1667_+8TAAATCAdelinsATTT mutation accounts for 25 % of the MLH1 mutant families. We used the national Danish hereditary nonpolyposis colorectal cancer register to estimate the cumulative lifetime risks for Lynch syndrome-associated cancer in 16 founder mutation families with comparison to 47 other MLH1 mutant families. The founder mutation conferred comparable risks for colorectal cancer (relative risks, RR, of 0.99 for males and 0.79 for females) and lower risks for extracolonic cancer (RR of 0.69 for endometrial cancer and 0.39 for all other extracolonic cancers). We also characterized expression of key Wnt-signaling proteins in colorectal cancers with the founder mutation. Aberrant staining affected beta-catenin in 59 %, E-cadherin in 68 %, TCF-4 in 94 % and Cyclin D1 in 68 % with extensive inter-tumor variability despite the same underlying germline mutation. In conclusion, the Danish MLH1 founder mutation that accounts for a significant proportion of Lynch syndrome and is associated with a lower risk for extracolonic cancers.
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| 8. |
- Therkildsen, Christina, et al.
(författare)
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Gain of chromosomal region 20q and loss of 18 discriminates between Lynch syndrome and familial colorectal cancer
- 2013
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Ingår i: European Journal of Cancer. - : Elsevier BV. - 1879-0852 .- 0959-8049. ; 49:6, s. 1226-1235
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Tidskriftsartikel (refereegranskat)abstract
- Lynch syndrome and familial colorectal cancer type X, FCCTX, represent the two predominant colorectal cancer syndromes. Whereas Lynch syndrome is clinically and genetically well defined, the genetic cause of FCCTX is unknown and genomic differences between Lynch syndrome and FCCTX tumours are largely unknown. We applied array-based comparative genomic hybridisation to 23 colorectal cancers from FCCTX with comparison to 23 Lynch syndrome tumours and to 45 sporadic colorectal cancers. FCCTX tumours showed genomic complexity with frequent gains on chromosomes 20q, 19 and 17 and losses of 18, 8p and 15. Gain of genetic material in two separate regions encompassing, 20q12-13.12 and 20q13.2-13.32, was identified in 65% of the FCCTX tumours. Gain of material on chromosome 20q and loss on chromosome 18 significantly discriminated colorectal cancers associated with FCCTX from Lynch syndrome, which likely signifies different preferred tumourigenic pathways. (C) 2012 Elsevier Ltd. All rights reserved.
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